1. Field of the Invention
The present invention relates to a method and device for self orienting a floating apparatus which utilizes an external magnetic field to maintain a constant orientation, and specifically relates to a plain form hydrometer, a floating thermometer, and a thermohydrometer that continuously display a graduated scale in an operator predetermined direction.
2. Discussion of the Related Art
Various instruments have been used by both industry and the home owner to measure properties such as the density, (weight per unit volume) specific gravity (weight per unit volume compared with water), or temperature of various liquids. Examples are floating thermometers, used to measure temperature, hydrometers used to measure density, and thermohydrometers which are a combination of a floating thermometer and a constant mass, variable displacement type hydrometer (xe2x80x9cplain form hydrometerxe2x80x9d). Plain form hydrometers and thermohydrometers (xe2x80x9cplain form instrumentsxe2x80x9d) have been made of either glass or plastic. These instruments typically comprise a body having a lower ballast section having a weight secured within this section for weighting of the instrument, and a stem portion that is integrally formed with the ballast. The stem contains a rolled scale that is numbered to correspond to the liquid being tested, and provide for a direct read-out of the desired measurement. Different scales have been utilized for different applications. For example, in determining specific gravity, the following scales have been used: Baume, API (petroleum), Proof and Tralle (alcohol), Brix (sugar), salt, and percentage scales. Fahrenheit, Celsius, and Kelvin temperature scales have also been utilized.
These instruments are used by placing them in the liquid in which a desired measurement is to be obtained. In the case of a hydrometer, an appropriate density of the liquid can be read from the scale contained within the stem of the device, determined by the amount the hydrometer extends into the liquid. Likewise, the temperature can be read from the face of the scale contained within a thermohydrometer or floating thermometer. Such floating hydrometers have been described, for example, in U.S. Pat. No. 4,993,263.
When instruments are floating in a liquid, they have a tendency to spin in circles, causing the scale to face away from the user. The user invariably has to gently touch the instrument or stretch his/her neck in order to read the scale.
Magnetic fields have been utilized to control the position of floating objects. U.S. Pat. No. 4,400,978 to Guay, et al, discloses an electronic hydrometer having an electronic circuit capable of automatically controlling the position of a float by means of a variable current supply and providing an output signal indicative of the density of a liquid. A permanent magnet is mounted in proximity of a connecting shaft which is secured to a float which is disposed within a liquid receiving chamber. The magnet is utilized in conjunction with an electronic circuit to maintain a plate mounted on the shaft in a reference position relative to a beam of light, and not to orient the scale to a predetermined position.
U.S. Pat. No. 3,964,317 to Blanchard discloses a densimeter which utilizes a float to sense a density of a fluid. Through the use of (1) an electric current, (2) a cylindrical coil connected to the end of a shaft which is connected to a float, and (3) a permanent magnet, the float is maintained at a selected vertical reference position. In the invention of the ""317 patent, the magnet does not orient the scale to a predetermined rotational position.
U.S. Pat. No. 5,848,029 to Chang and U.S. Pat. No. 5,893,789 to Wu utilize magnetic forces to control the movement of a floating toy. These toys are not used to provide a readout, are not used for measuring, and do not need to be positioned in a fixed direction relative to the user. Magnetic forces are used to provide random movement to the toy.
What is needed is a method and device to be used on a floating apparatus that will allow a readout to orient in a position such that the readout is continuously facing a predetermined direction.
Use of the term xe2x80x9crelated artxe2x80x9d is descriptive in nature only and references cited are not admitted to be xe2x80x9cprior artxe2x80x9d with respect to the present invention by their mention in this Background Section. All references cited are incorporated by reference as if fully set forth herein.
The present invention relates to a device for self orienting a readout integral to a floating apparatus utilizing a magnet integral to a container. For purposes of this invention, integral means positioned within, affixed to a wall, affixed within, engraved or etched or printed on a wall or otherwise located within or on the apparatus. The container may be of any size or shape having sufficient volume to float. The magnet and/or the readout can be embedded in a cylinder, attached externally to a cylinder, integral with a cylinder, or placed within a cylinder, being supported by the apparatus or supported by an additional structure within the apparatus.
One structure which accomplishes this comprises attaching an orienting magnet to a pin, the pin having a first and a second end. The orienting magnet is attached to the first end (pinhead) of the pin. The second end of the pin is affixed to the apparatus by a first means to allow the orienting magnet to resistively rotate. A second means is provided to rotate the orienting magnet to a predetermined position such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field.
The present invention also relates to a method for directionally orienting a readout of a floating apparatus which comprises the steps of:
a) integrating an orienting magnet to the floating apparatus,
b) orienting the magnet to a position relative to an external magnetic field, such that when the magnet aligns with the external magnetic field, a readout fixed to the floating apparatus orients itself to face a preselected direction. In one embodiment, the orienting magnet is integrated by resistively rotatably attaching.
The term xe2x80x9cresistively rotatably attachingxe2x80x9d means, for the purpose of this invention, the ability to rotate the orienting magnet only upon utilizing a force greater than the attractive forces between the orienting magnet and the apparatus, as explained in greater detail below.
A second embodiment comprises a device and method in which the orienting magnet is attached to the first end of the pin in a predetermined position. The second end of the pin is affixed to the apparatus so as to not allow the first permanent magnet to rotate, such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field.
A third embodiment comprises embedding an orienting magnet within or on the apparatus such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field.
Still another embodiment comprises either permanently or resistively rotatably affixing an orienting magnet to the readout and allowing the readout to float in a liquid contained within the apparatus such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field.
In particular, an advantage of the present invention is to provide a device and method such that a plain form hydrometer, a floating thermometer, a thermohydrometer, or other floating instrument can be inexpensively and conveniently preset to face a predetermined direction.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.